output. The default SEED is chosen at random, and contains enough
information to ensure that the output permutation is random.
suggestion from Feth AREZKI, Stephan Kasal, and Paul Eggert on 2003-07-17
+
+unexpand: [http://www.opengroup.org/onlinepubs/007908799/xcu/unexpand.html]
+ printf 'x\t \t y\n'|unexpand -t 8,9 should print its input, unmodified.
+ printf 'x\t \t y\n'|unexpand -t 5,8 should print "x\ty\n"